Configuring windows 2003 server radius authentiation (IAS ) for network dev

Hi,
I have configured Microfost windows 2003 server with IAS installed. I am trying to configure radius authentication for my network devices with AD user name and password. I followed the document http://articles.techrepublic.com.com/5100-1035_11-6182945.html. I have enterned below commands:

R1-871W(config)# aaa new-model
R1-871W(config)# radius-server host 192.168.1.10 auth-port 1645 acct-port 1646 key cisco
R1-871W(config)# ip radius source-interface Vlan2
R1-871W(config)# aaa authentication login TRAuthList group radius local

With the below commands, I am able to login only to user mode with the AD username and password. I am not able to login to enable mode of the device with the same AD username and password.
Any suggestions.